Over the past few years the powerful compact UV LED lamps have proved themselves remarkably – especially for magnetic particle testing and penetrant inspection by use of fluorescent materials.

The most important advantages of these lamps are the low power consumption (what enables battery or accumulator feeding), a very long lifetime, no warm-up time and above all the defined UV wavelength in the UV-A range (365 nm) with the emission half-width of 8.5 nm. This wavelength enables the maximum contrast between the crack indication and its background.

Through the narrow-bounded emission spectrum of UV light-emitting diodes there is no irradiation part, which bounds to visible range (from 400 nm) or lies within. The irradiation part in the visible range results in undesirable brightening and reflection, especially while testing metallic shiny, curved objects. Such reflections are not only perceived by an inspector as artifacts, they also reduce the contrast and therefore affect adversely the defect recognition.